The present invention relates to a surgical apparatus for the placement of an instrument within a body cavity. More particularly, the invention relates to an apparatus, device and method for end-to-end instrument placement.
Suprapubic catheters and instruments are used in many clinical settings including cases involving female incontinence, transurethral resection of the prostate where continuous irrigation is used, neurogenic bladders, spinal cord injury and other cases where bladder drainage and/or healing are desired. Additionally suprapubic instruments are used for inspection and therapy of the bladder, prostate, and/or ureter. Suprapubic catheterization offers a number of advantages over transurethral catheterization. These advantages include increased patient comfort, minimization of infection, improved irrigation and drainage during and after resection of the prostate, easier replacement and superior convenience during long-term catheterization, and improved evaluation of voiding and residual urine when applicable. Also, the suprapubic site is a convenient access route for instruments to observe and treat various conditions, the design, shape, and size of the instrument not being restricted by the shape and size of the urethra or concerns of urethral injury.
U.S. Pat. No. 4,684,369 discloses a needle for introducing a suprapubic bladder drainage instrument through the urethra. The needle is adapted to be attached at its rear end to a catheter which follows the needle through the urethra.
Current methods of placing suprapubic catheters are the "outside-to-inside" method and the less common "inside-to-outside" method. With the outside-to-inside approach, a sharp trocar or catheter-obturator combination is used to pierce from outside the body through the lower abdomen and into the bladder to create a passageway for pushing the catheter into the bladder. By comparison, the inside-to-outside method employs a grasping tool which is passed into the bladder via the urethra and, after positioning, can be pressed through the bladder and abdominal wall near the symphysis. Then grasping the catheter, it is used to pull the catheter into the bladder where the catheter may be released and left in a suprapubic placement.
While complications are rare, difficulties have been reported with percutaneous outside-to-inside suprapubic catheterization using a trocar. For example, the catheter may be placed accidentally outside of the bladder. The standard method of using a trocar/catheter arrangement does not always provide the accuracy and control needed for correct placement of the catheter. Also, outside-to-inside catheterization presents risk of injury to the floor of the bladder or damage to the bowel. Uncertainties in trocar alignment, orientation, or insertion distance can lead to such injuries. Thus, poor alignment or variable depth can result in perforation of the peritoneum, incomplete bladder entry, or penetration of the posterior bladder wall. Furthermore, due to a limited choice of catheter sizes and types, inadequate catheter lumen size may result. Finally, inappropriate suprapubic puncture size may result in extravasation of urine around the catheter or into the retroperitoneum.
Use of the inside-to-outside technique can minimize the above problems, but the lack of well designed devices for performing the procedure has limited its adoption. With the inside-to-outside method, a curved grasping tool is passed through the urethra and its tip is pushed against the bladder dome and anterior abdominal wall. Suprapubic palpation enables the practitioner to select a desired penetration site. The curved tool is pressed against the bladder dome and in some cases forced through the bladder, fascia, and abdominal wall. In other techniques, an incision is extended from the exterior abdominal wall on to the instrument tip permitting its advancement. Once outside the abdomen, the device is coupled to the drainage tube in some fashion so that the tube is guided into the bladder. Once within the bladder, the drainage tube is released. The device is then removed by way of the urethra.
While various instruments which utilize the inside-to-outside approach exist, none have coordinated the penetration, coupling, and release functions. Currently used instruments include the Lowsley retractor, uterine packing forceps (for females), and modified urethral sound. In general, these instruments require many steps, lack uniformity, and are not always readily available. Use of such instruments often results in ineffective penetration, inadvertent loss of the catheter, and poor sealing between the catheter and bladder wall.
Improvements in the suprapubic instrument placement may be applied to other medical applications. For example, in substantially non-invasive methods of internal operations, e.g. laproscopic surgery, the practitioner accesses internal organs through small incisions and working sheaths. The instruments used in such operations are generally elongate and adapted for use by way of these small incisions or sheaths. Accordingly, improvements in placement of suprapubic instruments, which are generally elongate instruments, may be applied to such substantially noninvasive operations.
Placing in-dwelling drainage tubes such as ureteral stents can be difficult due to their lack of column strength, frictional forces, and the fact that direct control of their proximal end is typically lost once the stent entirely enters a body lumen. Various placement techniques have been employed to overcome these problems, but without providing the extent of instrument placement control a practitioner would desire. Such placement techniques include stent placement over a guidewire using a pushing tube to advance the stent; stent placement on a wire where the stent, guidewire and pusher advance as one; and stent placement alongside a wire using a guide-eye where the stent is pushed internally or externally at its distal tip. In use of guidewire instrument placement methods, it is desirable to leave the guidewire as free as possible because the guidewire constitutes the primary instrument access route.
U.S. Pat. No. 4,824,435 issued Apr. 25, 1989 to Jerry D. Giesy and Matthew W. Hoskins, inventors herein, shows a guide-eye instrument guidance system wherein elongate flexible elements are guided into place within a tortuous body passage by providing the elements with annular guides adjacent their distal ends and sliding the elements over a guidewire within the passage. Column strength to move the elements through the body passage may be provided by a tubular pusher slidably received on the guidewire. Several instruments, each including an annular guide at its distal end, may be sequentially or simultaneously guided into place over a single guidewire.
Under the technique and apparatus disclosed in U.S. Pat. No. 4,824,435 the instrument to be placed is slidably coupled at its distal end to a guidewire. Such slidable coupling may include a loop formation at the distal end of the instrument to be placed. For tubular instruments, a lateral cut or slot in the tube wall near the distal end slidably receives the guidewire. To mount the instrument, the guidewire is threaded into the open distal end of the tube and then out the wall opening provided by the lateral cut or slot. In either case, the instrument to be placed is slidably coupled at its distal end to the guidewire. If the instrument itself has sufficient column strength, the instrument may be positioned by application of force at its proximal end as its distal end slides along the access pathway provided by the guidewire. For instruments having insufficient column strength, a tubular pusher may be slidably and concentrically received upon the guidewire. The distal end of the pusher engages the slidably mounted distal end of the instrument to be placed to move the instrument to be placed along the guidewire and into position.
While the apparatus and method of the system shown in U.S. Pat. No. 4,824,435 has proven useful in many cases, it lacks certain instrument positioning control desired by many practitioners. In particular, the disclosed system is generally limited to pushing of instruments along a guidewire. The practitioner has limited additional positioning control over the instrument to be placed, e.g., the practitioner typically cannot retract the instrument along the guidewire.
Various technologies have also been developed to address access problems in placement of instruments within a body lumen. These technologies include higher-column strength stents, hydrophilic-coated stents, stents of hybrid materials, locking devices to lock the stent, guidewire and pusher as one.
No one instrument placement method and apparatus provides complete and versatile positioning control, i.e., pushing, pulling, and twisting, of the instrument to be placed especially in the context of guidewire instrument placement. Furthermore, those instrument placement methods available often limit the practitioner in use of other associated instrument placement methods. Present positioning systems suffer certain limitations.
In a trailing suture design, i.e., a Lubri-Flex (Registered Trademark of Surgitek) hydrophilic-coated stent, the suture trails the stent and provides retraction control during placement. Once positioning is complete the suture can be cut and pulled out or left in for use later in removing the stent. This provides reasonable control, but can be cumbersome and makes desirable a more simple coupling system.
The Speed Lok (TM) ureteral stent set available from Boston Scientific Corporation under the Registered Trademark Microvasive, is limited to one pass placement. The guidewire, stent, and pusher are designed specifically to be pre-coupled as a placement system, and cannot be employed in connection with a separate or pre-existing guidewire. The system does not offer a clean release between the pusher or positioner device and the instrument to be placed. Removal of instrument placement components can affect the position of the instrument placed. Accordingly, upon removal of the placement system following positioning of the instrument to be placed, the instrument placed may have been dislodged from its desired position.
The Kwart retro-inject (TM) stent sets require different pusher/inserter sizes for stents of different sizes. As understood, the Kwart retro-inject system coaxially mounts a stent inserter sleeve, release sleeve, and the stent upon a guidewire. Manipulation of the stent, i.e., positioning of the stent, is provided by the frictional inter-relationship among the coaxially mounted elements. Once the stent is positioned, one of the coaxially mounted elements is removed from the system to frictionally disengage the stent from the remaining portions of the system. The remaining portions of the system are then withdrawn from the stent. Thus, the Kwart retro-inject system is not an end-to-end coupling mechanism, the elements are used in coaxial relation. Furthermore, because the various components must be specifically sized relative to one another in order to achieve the desired frictional relationship, the system lacks versatility with respect to stent diameters. For any given stent diameter, a separate placement system dedicated to that diameter is required.
It is desirable, therefore, that a guidewire instrument placement method and apparatus provide a broader range of positioning control capability across a broader range of instrument placement methods and devices. It is particularly desirable that better grasp and release features be available for instrument placement over an in-place guidewire.